AT&T 6300 Programmer's Manual page 346

LOG
Function
Syntax
Remarks
Example
7-190
Returns the natural logarithm of a positive
argument.
LOG(numexp)
LOG
is calculated in single precision, unless
you specify the
"ID" option when you invoke
GWBASIC.
If "numexp" is negative or zero an "Illegal
function call" error is returned.
PRINT LOG(45/7]
1.860752
Ok